Turn into a Pumpkin

• WOTC Official Reminder Textofficial rules
  Food — , , Sacrifice this artifact: You gain 3 life.

• WWizards of the Coast2019-10-04
  Official Ruling
  Adamant effects check what mana was actually spent to cast a spell. If an effect allows you to spend mana "as though it were mana" of any color or type, that allows you to spend mana you couldn't otherwise spend, but it doesn't change what mana you spent to cast the spell.
• WWizards of the Coast2019-10-04
  Official Ruling
  If an instant or sorcery spell has an adamant ability, you perform the spell's instructions in order. You don't perform the adamant instruction before the spell resolves or before any other effects printed above it.
• WWizards of the Coast2019-10-04
  Official Ruling
  If the target nonland permanent is an illegal target by the time Turn into a Pumpkin tries to resolve, the spell won't resolve. You won't draw a card, and you won't create a Food if you spent three blue mana to cast the spell.
• WWizards of the Coast2019-10-04
  Official Ruling
  If you copy a spell that has an adamant ability, no mana was spent to cast the copy at all, so that ability won't apply.
• WWizards of the Coast2019-10-04
  Official Ruling
  If an effect allows you to cast a spell without paying its mana cost, you can't choose to cast it and pay unless another rule or effect allows you to cast that spell for a cost. Similarly, you can't waive a cost reduction unless that effect says you may.
• WWizards of the Coast2024-11-08
  Official Ruling
  Whatever you do, don't eat the delicious cards.
• WWizards of the Coast2024-11-08
  Official Ruling
  You can't sacrifice a Food to pay multiple costs. For example, you can't sacrifice a Food token to activate its own ability and also to activate Maraleaf Rider's ability.
• WWizards of the Coast2024-11-08
  Official Ruling
  Food is an artifact type. Even though it appears on some creatures, it's never a creature type.
• WWizards of the Coast2024-11-08
  Official Ruling
  Some spells and abilities that create Food tokens may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't create any Food tokens.

Rulings via Scryfall